Filter construction and method of forming same

ABSTRACT

A filter construction is provided which is adapted for use at the downstream end of a tobacco rod. The filter embodies a smoke barrier which abruptly deflects the direction of flow of the smoke through the filter and causes the deflected smoke to pass through a plurality of perforations at a high velocity. The high velocity smoke impinges against a smoke impervious surface and is further deflected prior to being emitted from the filter. The impingement of the high velocity smoke causes solid and/or liquid particles entrained in the smoke to be deposited on the smoke impervious surface.

United States Patent Sherrill [451 Aug. 22, 1972 [541 FILTERCONSTRUCTION AND 851,773 4/1907 Pfortner.....'.....131/2l2 A ux 7 METHODOF FORMING SAME 1,545,147 7/1925 Levin ..131/2,61 B ux [72] Inventor,Joseph R Shem, winstomsalm 1,582,971 5/1926 Conley .1131 201 FOREIGNPATENTS OR APPLICATIONS [731 Assignee Reym'ds 1,508,121 11/1967 France.......131/261 B Winston-Salem, NC.

Filed: June 29, 1971 Appl. No.: 158,073

Related US. Application Data Continuation of Ser. No. 837,746, June 30,1969, abandoned.

References Cited UNITED STATES PATENTS Brawner ..l31/2l2 R Banderas etal. .....131/10.5 X Blount et a1. ..131/201 X Lebert ..'....131/10.5 XScott et a1 ..l31/10.5 UX

570,085 6/1945 GreatBritain ..13l/212A A filter construction is providedwhich is adapted for use at the downstream end of a tobacco rod. Thefilter' embodies a smoke barrier which abruptly deflects the directionof flow of the smoke through the filter and causes the deflected smoketo pass through a plurality of perforations at a high velocity. The highvelocity smoke impinges against a smoke impervious surface and isfurther deflected prior to being emitted from the filter. Theimpingement of the high velocity smoke causes solid and/or liquidparticles entrained in the smoke to be deposited on the smoke impervioussurface.

4 Claiim, 10 Drawing figures Patented Aug. 22, 1972 2 Sheets-Sheet lPatented Aug. 22, 1972 2 Sheets-Sheet 2 Iht/rr/dr James H. Sherri 59'-Pend/e-fonJ/eumgn,

FILTER CONSTRUCTION AND METHOD OF FORMING SAME BACKGROUND OF THEINVENTION Various filters for cigarettes and the like have heretoforebeen utilized; however, becauseof certain design characteristics, theyhave been beset with one or more of the following shortcomings: (a) theyare ineffective in removing the undesirable particles from the smoke asit passes therethrough; (b) they are of costly construction; and (c)they are difficult to form and are not suitable for high speedproduction.

SUMMARY OF THE INVENTION I Thus, it is an object of this invention toprovide a filter which overcomes the aforenoted shortcomings.

It is a further object of this invention to provide a filter which maybe formed by automatic equipment, the operation of which is wellunderstood in the cigarette-making art.

Further and additional objects will appear from the description,accompanying drawings, and appended claims.

In accordance with one embodiment of this invention, a filter forcigarettes or the like is provided which includes an outer sleeve unitwhich is afiixedly secured to one end of a tobacco rod. The outer sleeveunit is preferably formed of a smoke impervious sheet material such aspaper. Disposed within the outer sleeve unit is a second or inner sleeveunit. Portions of the exterior surface of the second sleeve unit arespacedfrom the interior surface of the outer unit and cooperatetherewith to form a shallow passageway which encircles the second unitand extends a predetermined longitudinal distance with respect thereto.The second unit is provided with at least one set of perforations, thelatter being arranged so as to substantially encircle the second sleeveunit. Disposed within the second sleeve unit and located downstream ofthe set of perforations is a smoke barrier piece, the periphery of whichis in sealing engagement with the interior surface of the second sleeveunit. The set of perforations is in communication with the shallowpassageway and because of the size of each perforation the smoke iscaused to pass therethrough at a high velocity into the shallowpassageway. Due to the high velocity of the smoke entering thepassageway and the close proximity of the interior surface of the outersleeve unit forming a wall of said passageway, solid and/or liquidparticles entrained in the smoke impinge against and are deposited uponsaid interior surface prior to the smoke being emitted from the filter.

DESCRIPTION For a more complete understanding of the invention,reference should be made to the drawings wherein:

FIG. 1 is a fragmentary perspective view of one form of the improvedfilter affixed to one end of a tobacco rod and showing the filter inlongitudinal section.

FIG. 2 is a fragmentary side elevational view of an elongated unitformed of a plurality of partially assembled filters of the typeillustrated in FIG. 1 and with the filters thereof arranged inalternately inverted end-toend relation, and showing one end of the unitin longitudinal section.

FIG. 3' is a side elevational view of a two-up filter piece severed fromthe unit of FIG. 2; said piece including an outer sleeve unit shown inlongitudinal section.

FIG. 4 is a longitudinal sectional view of a first modified form of theimproved filter.

FIG. 5 is a fragmentary perspective view partially in section of asecondmodified form of the improved filter and shown with the outersleeve unit removed.

FIG. 6 is similar to FIG. 5 but showing a third modified form of theimproved filter.

FIG. 7 is similar to FIG. 1 but showing a fourth modified form of theimproved filter affixed to one end ofatobacco rod.

FIG. 8 is a perspective longitudinal sectional view of a fifth modifiedform of the improved filter.

FIG. 9 is a perspective-view of the smoke barrier component for thefilter shown in FIG.- 8.

FIG. 10 is a fragmentary schematic view of a portion lustratedembodiment constitute the basic elements of a filter cigarette. The rod12 per se is not intended to be possessed of patentable invention andtherefore it may take various other forms from that shown withoutdeparting from the scope of the invention. The rod, as

shown, includes a core 14 formed primarily of compacted shreds ofblended types'of leaf tobacco. The extent to which the shreds arecompacted is carefully controlled so that smoke generated at the lightedend 13 may be readily drawn through the rod and out through thedownstream end 11 when only a small amount of suction is applied to thefree or discharge end 10a of the filter. The core is encompassed by anelongated sheet of suitable cigarette wrapping paper 15. The elongatededges of the wrapping 15 are normally secured by adhesive in anoverlapping relation.

The method of forming the rod 12, the component parts comprising same,and the equipment used in forming same are well known in thecigarette-making art. The initial length and diameter of the rod may bevaried as desired.

Filter 10, as illustrated in FIG. 1, includes a short tubular member 16'which abuts the rodend 11. The member 16 is preferably formed ofsuitable sheet material; however, if desired, it may be extruded fromsuitable plastic material which would not deleteriously affect theflavor and aroma of the smoke passing therethrough. Member 16 in theillustrated embodiment is provided with a relatively large centralopening.

Spaced a .predetermined distance downstream of member 16 is a smokebarrier piece 17 which may be formed of suitable plastic, paper pulp orthe like. Whatever the material of which the piece 17 is formed, it mustbe impervious to the smoke emitted from the end 11 of the rod 12. Inaddition to the barrier piece 17, there may also be provided a porousplug or mass 18 which provides a final filtering action on thecirculating I .sleeve unit 20 which snugly encompasses said componentparts. The unit 20 is preferably formed from suitable paper stock; butother suitable thin material, such as a plastic, may be used if desired.Prior to the paper stock being brought into encompassing relation withmember 16, piece 17, and plug 18, it has sets of perforations 21 and 22formed therein. The perfora tions comprising each set are arranged sothat they encircle the formed sleeve unit 20, see FIGS. 1 and 2. Thesets of perforations are spaced relative to one another so that set 21is disposed upstream of barrier piece 17 and set 22 is disposeddownstream thereof.

Encompassinginner sleeve 20. is an outer or second sleeve unit 23 whichis formed from a sheet of smoke impervious material such as paper. Theinterior surface of unit 23 is heldin closely spaced relation withrespect to the exterior surface of unit 20 by a pair of spacer elements24 and 25. Each element may be formed from a narrow strip of sheetmaterial which is adhesively applied to the exterior surface of unit20'and completely encircles same. It will be noted that elements 24 and25 are positioned relativeto one another so that both sets ofperforations 21 and 22 are disposed therebetween. The spacing 26, whichis formed between spacer elewith one anotheronly through passageway 26.It will be and is forced to flow inwardly through the set 22 ofperforations. It is preferred that the size of perforations 22 be largerthan perforations 21 so as to minimize the pressure drop which mightoccur by reason of the filter.

FIG. 2 illustrates one method by which the filter is formed. Inpracticing this method, the inner sleeve unit is formed from a web ofpaper or the like which has been previously perforated so as to form thesets of perforations. As the web travels through the forming machine andprior to said web'being shaped into an elongated tubular unit 28, ,seeFIG. '2, a plurality of members A, barrier pieces 17, and plugs B arefed out and spotted onto the traveling web surface by conventional meanswell known in the cigarette-making industry. Members A and plugs B areof such axial dimensions that, when subsequently cut, they will formtwo' members 16 and two plugs 18, respectively, of the required length.Once the components A, 17, and B are in proper relative positions, theweb passes suitable plows which will form the web into the elongatedtubular unit 28. After unit 28 has been formed, the spacer elements Care applied by adhesive or'the like to the exterior surface of the unitby conventional methods. Elements C are of double axial dimension sothat when the unit 28 is subsequently cut, each element C will ments 24and25 and the interior and exterior surfaces noted that passageway 26providesa means for the smoke to circumvent barrier piece 17 when it isdrawn through the filter. In the illustrated filter 10, both units 20and 23 are coextensive with one another. Outer sleeve unit 23 may besecured to the end 11 of therod 12 by tipping 27 which is preferablyformed of a suitable paper material, but other suitable thin materialmay also be used.

Thus, with filter 10, when the smoke is drawn therethrough, it willfirst flow through the center opening in member 16 and then, because ofbarrier piece I I 17, will be deflected and forced to flow outwardlythrough the perforations comprising set 21. The'perforations aresymmetrically arranged about the unit 20 and are sized so that the smokewhen passing therethrough will attain a high velocity. Because of theshallowness of passageway 26, the high velocity smoke, upon leaving theperforations 21 in the form of jets, will impinge with considerableforce against the portions of interior surface of unit 23 which aredirectly opposite the perforations 21 andcause the direction of flow tobe abruptly changed. When this abrupt change in flow direction occurs, avery substantial number of the relatively heavy solid and/or liquidparticles, which are entrained in the high velocity smoke, will bedeposited upon the interior surface of unit 23.

; Subsequent to impinging the interior surface, thesmoke travelsrearwardly or downstream along passageway 26 until it abuts spacerelement 25 w ereupon it again encounters an abrupt change of directionform elements 24 and 25. The spacing between adjacent elements C on theunit 28 is such that as each element C, or altemate elements C, aremoved into alignment with the cutting blade (the plane of which is shownin a dotted line 30 in FIG. 2) either a section having an axial lengthequal to a single or'double filter will be formed.

Before or after the section is cut, the exterior surface 7 formed. Theattachment of the rods to the section I and the subsequent cutting ofthe latter are performed in a manner also well understood in thecigarette-making art.

In lieu of the spacer elements 24 and 25, the outer surface of the innersleeve unit 20 or the interior surface of the outer sleeve unit 23 maybe embossed so as to form outwardly or inwardly extending ribs whichwould serve to provide the desired spacing'between the sleeve unitsdefining the shallow passageway 26.

FIG. 4 discloses a modified filter 10A wherein a barrier piece 31 hasbeen provided which includes a disc shaped upstream end 32 and adownstream rodlike end 33 of reduced diameter. The outside diameter ofend 32 is dimensioned so that it is in sealing engagement with innersleeve unit 20. The axial length of end 33, on the other hand, is suchthat it provides the proper axial spacing between disc-shaped end 32 anda plug, not shown, if one is to be used. The latter plug would be of thesame construction as plug 18 previously described.

If desired, the plug may be omitted entirely whereupon the length of end33 may be longer.

The outside diameter of end 33 is such that it will form a secondshallow passageway 34 between the interior surface of the inner unit 20and the exterior of the rodlike end 33. The second shallow passageway34v extends from the downstream side of the disc-like end 32 to eitherthe end of the filter or a plug, whichever the case may be.

With the modified filter A, the smoke enters the first shallowpassageway 26 in the same way as previously described for filter l0, andthen it flows from passageway 26 intosecond shallow passageway 34through the second set of perforations 22. By reason of the shallownessof passageway 34 and the disposition of perforations 22, the smoke uponentering passageway 34 will impinge against the exterior surface of therodlike end 33 and cause whatever solid and/or liquid particles stillentrained in the smoke to be deposited thereon. Barrier member 31 may beformed of plastic, paper pulp or other suitable material.

FIG. 5 illustrates another modified partially assembled filter 10Bwherein an inner sleeve unit 35 formed of suitable plastic or the likeis provided. Unit 35 has shoulders 36 formed at opposite ends thereofwhich serve the same function as spacer elements 24 and 25 previouslydescribed.

In place of the tubular member 16, barrier piece 17 and plug 18 asincorporated in filter 10, a single insert 37 is provided in filter.10B. Insert 37 is preferably formed from bar stock which has beenextruded or otherwise formed. The axial length of insert 37 coincidessubstantially with that of sleeve unit 35 so that the upstream end 38 ofinsert 37 will abut the end 11 of the tobacco rod 12, and the downstreamend 40 of the insert 37 will terminate at the free end of the filter orat a plug, similar to plug 18, whichever the case may be.

To facilitate assembly of filter 10B the unit 35 may comprisetwo'half-cylinder sections, not shown, which are bonded to one anotheralong their respective longitudinally extending edges. Prior to bondingthe halfcylinder sections, the insert 37 is properly positionedtherebetween.

At approximately mid-length of insert 37, it will be noted there isprovided an outwardly extending annular flange 41. The outer peripheryof the flange is in sealing engagement with the portion 42 of unit 35,which is disposed between the sets of perforations 21 and 22.

FIG. 6 shows another modified filter 10C which substitutes a ball orspherical piece 43 of suitable smoke impervious material for the insert37. The diameter of the ball 43 corresponds to the outer diameter ofinsert flange 41. One advantage of utilizing the ball 43 is that greatertolerance is permitted in spotting the ball between the sets ofperforations 21 and 22. Because of the snug fit between the ball 43 andsleeve unit 35, when the latter is formed, the ball will remain in afixed position therein. If desired, however, adhesive may be utilized toretain the ball in a fixed position within the sleeve unit.

FIG. 7 shows still another modified filter 10D wherein the outer sleeveunit 44 is formed of plastic or other suitable material, and at oppositeends thereof there are formed inwardly extending flanges or shoulders 45and 46. The extent to which the shoulders 45 and 46 project willdetermine the shallowness of passageway 26. Shoulders 45 and 46 take theplace of the shoulders 36 formed in filter 10B and C, and the spacerelements 24 and 25 of filter 10. In filter 10D, the tubular member 16 offilter 10 has been eliminated and instead the upstream ends of innerunit 20 and outer unit 44' abut the end 11 of the tobacco rod '12.

In instances where unit 44 is plastic, the unit is formed from twohalf-cylinder sections, which are bonded together after barrier piece 17and plug 18 have been properly positioned therein, in a manner similarto that described for filters 10B and C.

' FIG. 8 illustrates another modified filter 10E.wherein an elongatedinsert 47 is substituted for'the barrier piece 17 and plug 18 of filter10D. Insert 47 closely resembles insert 37 of filter 10B; however, theexterior surfaces of both the downstream and upstream ends 48 and 50 ofinsert 47 have formed thereon a plurality of symmetrically arrangedelongated longitudinally ex tending ribs 51. Each rib 51 engages andbraces the interior surface of the sleeve unit 20. Thus, betweenadjacent ribs 51 there is provided narrow, shallow channels 52 throughwhich the smoke travels before it passes through perforations 21 andafter it passes through perforations 22. As in the case of insert 37,insert 47 may be formed of plastic or other suitable material which hasbeen extruded or otherwise formed.

FIG. 10 shows schematically a portion of one type of I apparatus whichmight be used in assemblingfilter 10E. With such apparatus, a rod 53,comprising a plurality of inserts 47 integrally connected in end-to-endrelation, is fed intermittently in an axial direction at a predeterminedrate. by a pair of power driven feed wheels 54a and b. Each of saidwheels has a toothed periphery which engages the channels 52 formedbetween the ribs 51 of the insert. An extruder, not shown, may becoupled directly to theinfeed end (right-hand end as seen in FIG. 10) ofthe apparatus, in which case the wheels 54a and b will be fast formingwheels which form channels 52 or other desired configurations. Spaced apredetermined distance downstream of wheels 54a and b, a web 55of paperor the like, having sets of perforations 21 and 22 formed therein, isbrought into encompassing relation with the moving rod 53. The web 55 istaken from a bobbin or spool 56. lfdesired, the web 55 may be perforatedsubsequentto being withdrawn from the bobbin 56. Along with the sets ofperforations 21 and 22, a registering stripe can be printed on the webwhich will facilitate properly registering the sets of perforations onthe rod 53'and also registering the encased rod 53 within the outersleeve unit 44.

Just prior to the web 55 contacting rod 53, it is engaged and subtendedby a driven belt .57. The belt 57, web 55 and rod 53 then move past aconventional folder bottom 58, the structure and function of which arewell known in the cigarette-making art. Upon leaving the folder. bottom58, the rod 53 is completely encased within a sleeve formed from web.55and then passes between a second pair of wheels 60a and b. Carried onthe periphery of each wheel 60a and b are halfcylinder sections whichcooperate to form outer sleeve unit 44. Prior to each half-cylindersection reaching the encased rod 53, a suitable adhesive is applied tothe exposed elongated mating edges of the half-cylinder sections. Inplace of adhesive, the two half-cylinder sections can be held in matingrelation by a suitable wrapping of paper, not shown.

lf'desired, the wheels 60a and b may be heated by suitable heatingelements which would facilitate bonding of the half-cylinder sectionstogether. At a predetermined station, not shown, downstream of wheels60a and-b, the rod 53, which is encased in web 55 and successive sleeveunits 44, is cut into appropriate lengths to which one or more tobaccorods are subsequently attached.

Similar apparatus may be utilized in assembling fil-. ters 108, C and D.in any case, the manner of assembling the various components comprisingthe filter is performed expeditiously by utilizing equipment andtechniqueswell understood in the cigarette-making art and thus suchmanner of assembly is compatible with the equipment and techniquesutilized in forming the tobacco rods and the like.

Thus, it will be seen that a filter has been provided which utilizes animpingement action to effectively remove solid and/or liquid particlesfrom the smoke. In

addition, the improved filter may be quickly and automaticallyassembled.

Iclaim: l. A disposable filter affixed to the downstream end of anelongated tobacco rod, said filter comprising a cylindrical end memberpositioned adjacent the material encompassing first unit wherebypredetermined segments of the first unit exterior surface'and shallowsecond'passageway having a smoke discharge jacent to but spaced from theinterior surface of said downstream end of the rod, said end memberbeing provided with a passageway through which smoke from the tobaccorod is caused to flow longitudinally upon leaving the rod downstreamend; a substantially rigid smoke barrier piece disposed in predeterminedspaced,

aligned, downstream relation with respect to the downstream end of saidend member; a thin wall first sleeve unit of a flexible sheet materialencompassing and sealingly contacting the outer periphery of said endmember and said barrier piece and retaining same in said predeterminedspaced relation, said first sleeve unit being provided with a set ofsmall perforations arranged in sleeve unit-encircling relation and inregistration with the space between the end member and said barrierpiece and through which the smoke is caused to flow outwardly as highvelocity smoke jets; and a smoke impervious second sleeve unit of aflexible sheet end disposed downstream of said barrier piece.

2. The filter of claim 1 including an elongated rodlike member extendingdownstream from said barrier piece,

the exterior of said rodlike member being closely adfirst sleeve unit;said first sleeve unit including a second set of small perforationsarranged in sleeve-unit encircling relation and disposed downstream ofsaid first set v of perforations and said barrier piece, said shallowsecond passageway being closed off downstream of said second set ofperforations whereby smoke flows from said second. passageway inwardlythrough said second 7 312%?! 3%58 rodlike member disposed opposite theperforations of said second set prior to the smoke being emitted fromthe downstream end of said filter.

3. The filter of claim 2 wherein the barrier piece and the rodlikemember are in the form of coaxial cylinders, the former having a radiusgreater than that'of the latter.

4. The filter of claim 3 wherein the barrier piece and

1. A disposable filter affixed to the downstream end of an elongatedtobacco rod, said filter comprising a cylindrical end member positionedadjacent the downstream end of the rod, said end member being providedwith a passageway through which smoke from the tobacco rod is caused toflow longitudinally upon leaving the rod downstream end; a substantiallyrigid smoke barrier piece disposed in predetermined spaced, aligned,downstream relation with respect to the downstream end of said endmember; a thin wall first sleeve unit of a flexible sheet materialencompassing and sealingly contacting the outer periphery of said endmember and said barrier piece and retaining same in said predeterminedspaced relation, said first sleeve unit being provided with a set ofsmall perforations arranged in sleeve unit-encircling relation and inregistration with the space between the end member and said barrierpiece and through which the smoke is caused to flow outwardly as highvelocity smoke jets; and a smoke impervious second sleeve unit of aflexible sheet material encompassing said first unit wherebypredetermined segments of the first unit exterior surface and the secondunit interior surface are in closely spaced relation and form a shallowsecond passageway communicating with said set of perforations andcircumventing said barrier piece, the high velocity smoke jets uponbeing emitted outwardly from said set of perforations impinging againstthe closely adjacent portions of the interior surface segment of saidsecoNd unit uniformly spaced radially outwardly of said perforationscausing deposition thereon of solid and liquid particles entrained inthe high velocity smoke jets, said shallow second passageway having asmoke discharge end disposed downstream of said barrier piece.
 2. Thefilter of claim 1 including an elongated rodlike member extendingdownstream from said barrier piece, the exterior of said rodlike memberbeing closely adjacent to but spaced from the interior surface of saidfirst sleeve unit; said first sleeve unit including a second set ofsmall perforations arranged in sleeve-unit encircling relation anddisposed downstream of said first set of perforations and said barrierpiece, said shallow second passageway being closed off downstream ofsaid second set of perforations whereby smoke flows from said secondpassageway inwardly through said second set of perforations as aplurality of high velocity smoke jets and impinges against portions ofthe exterior of said rodlike member disposed opposite the perforationsof said second set prior to the smoke being emitted from the downstreamend of said filter.
 3. The filter of claim 2 wherein the barrier pieceand the rodlike member are in the form of coaxial cylinders, the formerhaving a radius greater than that of the latter.
 4. The filter of claim3 wherein the barrier piece and the rodlike member are of unitaryconstruction and the outer cylindrical surface of said barrier piece isin sealing contact with the first sleeve unit.